newbie question about sorting a 4x5 enlarger

I'm refurbishing a rescued (from a university bin) DeVere 54 enlarger. It
was minus baseboard, lens panel and lens (but bellows still present) and
light source, all of which have been made good by DIY methods and eBay.
(Light source is a ply box lined with mirrors and with 4 x 60W bulbs, shone
through an opal glass diffuser). It's all but ready to go, initially for
printing my pinhole 6x12negs but later for when I get/build a 5x4 field
camera. I have two queries for those who might know:

1) to check the lens and light were focussing OK, I made a cutout cross
to go in the neg holder. Focus range and sharpness were excellent but,
sliding the head up and down the twin sliders, the centre of the cross
veered in a diagonal direction across the baseboard, the variation being
about an inch over the whole height variation (three feet?). So something
isn't aligned dead vertical. How could I correct this deviation and does it
matter? It means there must be a tiny bit of variation across the focal
plane from corner to corner but will it show up? The lens is f/4.5 wide open
so a couple of stops down it's f/9 - dunno what depth of field that gives.

(I will admit that the baseboard as tested was thick MDF NOT braced,
just bolted tight to the deVere's cast feet. I've since braced the bottom
board with some 2x2").

2) The DeVere counterbalances the weight of the head with a spring-wound
pulley shaft at the bottom that bears on a steel cable via a pulley at the
top. Sliding is locked and unlocked by a lift-up lever that releases/applies
a brake (bicycle brake pad!) to one of the sliders. As set up, the spring is
stronger than the head, so the head will not stay still with the brake on,
especially at the bottom position (cable tightest). I can get it to "float"
satisfactorily by adding two housebricks on the lamp head but extra weight's
going to make it wobble and I don't want the hassle of semi-permanently
attaching the enlarger to a wall if avoidable. Does anyone have experience
of taking a turn or so off the spring to lower the tension? I don't want to
fiddle with this without guidance, as the spring tension on that shaft is
pretty fearsome and I don't want to undo something that'll slam off
violently in my face and be impossible to retension! Extra weight could be
aligned with the sliders - plates of scrap lead attached to the chassis -
rather than on the head where it'll add to the bending moment and hence
wobble.

Awaiting guidance, bigformatters, and TIA,

Tony Clarke

Tony Clarke spake thus:

1) to check the lens and light were focussing OK, I made a cutout cross
to go in the neg holder. Focus range and sharpness were excellent but,
sliding the head up and down the twin sliders, the centre of the cross
veered in a diagonal direction across the baseboard, the variation being
about an inch over the whole height variation (three feet?). So something
isn't aligned dead vertical. How could I correct this deviation and does it
matter? It means there must be a tiny bit of variation across the focal
plane from corner to corner but will it show up? The lens is f/4.5 wide open
so a couple of stops down it's f/9 - dunno what depth of field that gives.

To answer this question, yes: your enlarger as currently set up has a
severe case of misalignment: an inch over the whole height range is
*huge*. It will definitely affect image quality. But it may be easily
correctable.

Here's what a guy would want to do: Get yourself a mirror you can cut up
into pieces, preferably thin glass (single strength, as it's called here
in the US), and a glass cutter. (Sounds like you're familiar with DIY
stuff.)

Cut one piece that you can place in the negative carrier, where the film
goes. Make another, larger piece that will go on the baseboard. Make
the first piece narrow enough to go into the neg. carrier but at least a
couple of inches wide, and long enough to stick out clear of the
negative carrier about 6 inches or so.

In this narrow piece, you'll need to remove the reflective coating in a
small spot, somewhere near the end of the piece. Scrape the coating off
in a small circle, say about 1/2". Doesn't have to be neat, but you need
to be able to see through it.

On the reflective surface of the mirror, make a highly-visible marker
around the scraped-off circle. A paper reinforcement circle will work
nicely, or cut one out of some self-adhesive label stock, or use paint.
Again, doesn't have to be neat, but needs to be visible.

Stick the narrow piece in the negative carrier, reflective side down.
Crank up the enlarger at least halfway (the higher the better). Place
the other mirror face-up on the baseboard.

Here's how the alignment procedure works: you sight down through the
hole in the top mirror at the mirror on the baseboard. You should be
able to see the reflection of the circle around the hole. A light
shining upward at the upper mirror will help.

What you'll see is a "hall of mirrors" effect of multiple reflections.
When the enlarger is aligned with the baseboard, you'll see just a
single hole reflected straight back to you; when it's misaligned, you'll
see a receding line of reflections. The direction in which the line
veers will tell you which way the enlarger head needs to be moved.

I have no idea how to adjust your particular enlarger, but there is
certainly some way to do it. You'll need to find the fasterners to
loosen to move the enlarger head (or column) in both axes in relation to
the baseboard.

This is a very accurate way to align any enlarger.


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"David Nebenzahl" wrote in message
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[SNIP]

This is a very accurate way to align any enlarger.


I second that. Hasselblad used to sell a pair of mirrors set up like that
to use when aligning a camera parallel to a base-board for copy work.


Peter